Exhaust aftertreatment systems are used to receive and treat exhaust gas generated by IC engines. Conventional exhaust gas aftertreatment systems include any of several different components to reduce the levels of harmful exhaust emissions present in exhaust gas. For example, certain exhaust aftertreatment systems for diesel-powered IC engines include a selective catalytic reduction (SCR) catalyst to convert NOx (NO and NO2 in some fraction) into harmless nitrogen gas (N2) and water vapor (H2O) in the presence of ammonia (NH3). Generally in such conventional aftertreatment systems, an exhaust reductant, (e.g., a diesel exhaust fluid such as urea) is injected into the aftertreatment system to provide a source of ammonia, and mixed with the exhaust gas to partially reduce the NOx gases. The reduction byproducts of the exhaust gas are then fluidically communicated to the catalyst included in the SCR aftertreatment system to decompose substantially all of the NOx gases into relatively harmless byproducts which are expelled out of such conventional SCR aftertreatment systems.
In conventional SCR systems for the aftertreatment of exhaust gas (e.g., diesel exhaust gas), an exhaust reductant (e.g., a source of ammonia such as urea) is inserted into the SCR system to facilitate reduction of NOx gases included in the exhaust gas of IC engines (e.g., diesel exhaust gas). The exhaust reductant inserted into the SCR system can impinge the sidewalls of the SCR system and be deposited on a sidewall of the SCR system in the form of solid crystals (e.g., stalagmite and/or stalactite) crystals. Such solid deposits can decrease the flow path of the exhaust gas, produce unwanted turbulence, increase the backpressure of the exhaust gas, which can lead to decreased fuel efficiency and eventual failure of the aftertreatment system.